In the farthest right pic there is evidence of subterrnean termite-you can see the layers of wood (hard wood) that they don't eat. This is only indicative of sub termites. The absence of mud may mean it's old or that the wood pecker theory(or some other predator) exposed them, and cleard it while trying to get a meal. Sub termites have a few defenses they use and one is to simply vacate the area. My guess is that there is more damage and mud behind the wood. Here is a link to show you the damage of termites and how it is almost always hidden until exposed.
Termites | Pest Cemetery
Also I'm not sure it's wood pecker.....Just a guess but it doesn't look at all like the holes they drill. Have an exterminator come out to look for sure.There could be hidden damage